Glia dysfunction in schizophrenia: evidence of possible therapeutic effects of nervonic acid in a preclinical model

Neuroinflammation may inhibit oligodendrocyte and astrocyte differentiation, which causes demyelination and synaptic degeneration. The myelin component nervonic acid (NA) may improve demyelinating and neurodegenerative diseases.

This study firstly explored relationships between glial cell dysfunction and demyelination or synaptic degeneration in schizophrenia patients, and secondly determined nervonic acid therapeutic effects in a preclinical schizophrenia model of mice.

Plasma samples were collected from 18 male healthy controls and 18 male schizophrenic patients (diagnosed by DSM-V) at aged 18–55. Mouse brain samples were collected from a maternal immune activation (MIA) model of schizophrenia via injecting 5 mg/kg polyinosinic-polycytidylic acid. Male mouse offspring (age 2.5 months, n = 12) were treated by clozapine (15 mg/kg/day) or fed 0.5% NA for 6 weeks. Cytokine and dopamine (DA) concentrations, and glial phenotypes and myelin markers were measured in both human plasma and mouse brain samples.

In patient plasma, increased proinflammatory cytokines were associated with reactive microglia (Iba-1) up-regulation, while decreased anti-inflammatory cytokines were related to microglia (CD206) downregulation. Decreased astrocyte marker (p11) concentrations were accompanied by reduced concentrations of oligodendrocyte and synaptic markers. However, NA and DA contents were increased. Compared with control mice, SZ-like behaviors appeared in MIA male mice. Changes in microglia and astrocytes markers, and cytokine concentrations in the frontal cortex were consistent with those observed in patients’ plasma. Hippocampal oligodendrocyte and synaptic marker expression were also decreased. DA content and DA/metabolite (DAPOC) were increased in MIA mouse brains. Most of these changes were normalized by both clozapine and NA. Even though some NA effects were more pronounced than clozapine, only clozapine restored cytokine function.

The data suggest a possible therapeutic route for schizophrenia patients.